The Riverside Schools in California desegregated gradually, beginning in 1965. Three segregated minority schools were closed and the students bused to white neighborhoods. This evaluation report analyzes longitudinally and in cross-section the achievement of students in desegregated schools. In the former analysis, pupils who were in grades K-3 the first year of desegregation are studied. The standardized achievement scores of these students are compared each year with the scores of all students in the district at the same level. It is concluded that: the achievement of bused pupils did not increase; the achievement of pupils desegregated in grade 2 or earlier neither increased nor decreased; and, the achievement of pupils desegregated after grade 2 decreased in comparison to that of other pupils. The cross-sectional analysis included all bused and receiving pupil grades K-3 each year, from 1965-66 through 1969-70. This study found that: the achievement of pupils in grades K-3 increased from 1966 to 1970; the achievement of bused pupils in kindergarten was significantly higher in 1970 than in 1966, while that of pupils in grades 2 and 3 was slightly lower; and, bused pupils in grades 2 and 3 with low and average achievement achieved less in desegregated schools than they had done in segregated schools. (Author/JW)